Process and apparatus for treating hydrocarbon oils



J. G. ALTHl-:R 2,063,072

PROCESS AND APPARATUS FOR TREATING HYDROCARBON OILS Dec. 8, 1936.

N @NBC uw@ Patented Dec. 8, 1936 UMTED STATES PATENT OFFICEI PROCESS AND APPARATUS FOR TREATING HYDROCARBON OILS Application October 31, 1930, Serial No. 492,386 Renewed October 17, 1935 claims. (ci. 19a- 48) This inventi'on vrelates to the treatment of hydrocarbon oils and particularly refers .to animproved method and means of simultaneously top ping and cracking petroleum. T'he invention provides for topping a crudetraw oil charging stock in a zone surrounding the fractionating device of a cracking system wherein the topped raw oil is subjected to conversion, the heat for topping the raw oil being supplied by the cracked vapors undergoing fractionation.

Referring to the attached diagrammatic drawing, the description of which embraces a description of the preferred operation of the process as Well as one form of apparatus in which this operation may be practiced: Raw oil charging stock containing a substantial proportion of material boiling within the range of motor fuel is supplied through line I and valve 2 to pump 3, is fed through line 4 and valve 5 into the annular space 6 located between the outer shelly of fractionating column 1 and the jacket 8 which surrounds the fractionating zone. The oil may, if desired, be first preheated by passing it through line 56, valve 51, coil 58, line 59 and valve 60 back into line 4 and thence to topping `zone 6. The oil thuspreheated also serves to assist fractionation of the vapors in fractionator 1. 'I'he oil introduced into this topping zone 5 receives sufcient heat. from the cracked vapors undergoing fractionation in fractlonator 1 to vaporize substantially all of its light components and particularly those which correspond in boiling range to motor fuel. Vapors from the topping zone' are Withdrawn through line 9 and valve I0 to fractionator II where their heavier portions, preferably those boiling above the range of motor fuel, are condensed and returned as reflux condensate throughline I2, valve I3, pump I4, line I5 and valve I6 to fractionator 1. Light fractionated vapors from fractionator II pass through line I 1 and valve I8, are subjected to condensation and cooling in condenser i9, products from which pass through line and valve 2| to be collected in receiver 22. Condensed distillate may be withdrawn from receiver 22 through line 23 and valve 24. Uncondensed vapors and gas may be released through line 25 controlled by valve 2B.

That portion of the rawoil charging stock remaining unvaporized in the topping zone is withdrawn therefrom through line 21 and valve 28 to pump 29 by means of which it may be fed through line 6I and valve 62 intoffractionator 1, coming in direct contact with the relatively hot vapors in this zone and assisting their fractionation, or the topped raw oil may be fed through line 30, valve 3| and line 32 direct to heating element 33. Heating element 33 is located in any suitable form of furnace 34 and the oil passing therethrough is heated to the desired conversion temperature under any desired pressure conditions passing 5 therefrom through line 35 and valve 36 to reaction chamber 31.

Separation of vapors and liquid is permitted in chamber 31, the unvaporized residual liquid being withdrawn through line 38 and valve 39 to 10 storage or to further treatment as desired. Vapors from reaction chamber 31 pass through line 40 and valve 4I to fractionator 1 wherein their heavier insuciently converted portions are condensed, returning as reflux condensate, together 15 with reflux condensate from fractionator I I and any raw oil', introduced into this zone as already described, through line 42 and valve 43 to pump 44 from which they are fed through line 32 and valve 45 to heating element 33 to undergo reconversion together with the topped raw oil charging stock fed to the heating element, as already described.

Light fractionated vapors from fractionator 1 pass through line 46 and valve 41, are subjected to condensation and coolingV in condenser 48 products from which pass through line 49 and valve 50 to be collected in receiver 5I. Condensed distillate may be withdrawn Afrom receiver 5I through line 52 and valve 53. Uncondensed vvapor and gas may be released through line 54 controlled by valve 55.

A portion of the condensed distillate from either receiver 5I or receiver 22, or both, may be returned, by well known means not shown in the 35 drawing, to fractionator 1 or to fractionator II or in part to both to assist fractionation of the vapors in these zones.

Conversion temperatures employed in the cracking system may be within the range of 40 liquid-vapor-phase crackingtemperatures say from 750 to 950 F., or may be of the higher order commonly termed vapor-phase cracking temperatures ranging sayfrom 950 to 1200 more or less. 45

Pressures employed in the cracking system may range from sub-atmospheric to super-atmospheric pressures as high as 2000 pounds or more per sq. in. and may besubstantially equalized throughout the cracking system or may vary be- 50 tween the different elements of the system. Preferably substantially atmospheric pressures' are employed in the topping system although sub-atmospheric or relatively low super-atmospheric pressures may be utilized, if desired.V 55

Continent crude oil containing approximately 20 percent motor fuel is iheated in the topping zone under`substantially atmospheric pressure to a.l

temperature of about 550 F. About-20 percent of straight-run gasoline is recovered from the topping system and the remaining 80 percent or thereabouts comprising unvaporized oil lfrom the 10 topping zone and reux condensate from the fractionator of the topping system is fed to the cracking system substantially in the manner shown in the drawing and is subjected together with reflux condensate from the fractionator of the cracking system to a conversion temperature of about 900 F. under a' super-atmospheric pressure of approximately 200 pounds per sqjin. This pressure is substantially equalized throughout the cracking system.

Based on the oil charged to the cracking system about 64 percent of pressure distillate containing some 80 percent of motor fuel having good anti-knock qualities is obtained' in addition to about 26 percent of good quality residual oil suitable for use as fuel, is obtained.

In another operation in which the conversion temperature is increased to about 950 F. and the pressure increased to about 225 pounds per sq. in. the production of motor fuel, based on the oil some 60 percent and shows a higher anti-knock value than that made under lower temperature conditions. The production of gas is, however, somewhat increasedand only substantially dry coke is recovered as the residual product from the system. The coke, gas and loss in this case amounts to some 25 percent of the cracking stock.

I claim as my invention:

l. An apparatus for use in oil distillation comprising a cracking system, a fractionating column forming an element in said system, a shell surrounding said column and adapted to receivel cold oil therein in heat exchange relationship with the vapors in the column, an oil inlet passage in the shell, a vapor outlet passage and a liquid outlet passage in the shell adapted to permit removal of the heated hydrocarbon products, a second fractionating column connected with the vapor outlet passage, said column having-a connection with the first vnax'necl fractionating column to permit the passage of reflux condensate from the second to the-first named fractionating column, and final condensing means communicating with said columns.

2. An apparatus for use in-oil distillation comprising a cracking system, a fractionating column 50 -Iwith the vapors in the column, an oil inlet passage v/`/ in the shell, a vapor outlet passage .and a. liquid outlet passage in the shell adapted to permit removal of the heated hydrocarbon products, a second fractionating column connected with the vapor outlet passage",'- said column having a connection with the first named fractionating column tof permit the passage ofvreflux condensate from the second to the rst named fractionating column, a connection beingprovlded between the iiquid\ outlet in'the shell, 'and the cracking system td permit passage of liquid from the shell to the cracking system, and final condensing means communicating with said columns.

3. A process which comprisessubjecting hydro- 75 carbon oil to cracking conditions of temperature charged to the cracking system, is increased to and pressure in a cracking zone, removing cracked vapors from said zone and dephlegmating the same in a fractionating zone to condense insufficiently cracked fractions thereof, heating crude oil containing natural gasoline in indirect heat exchange relation with the cracked vapors undergoing dephlegmation by introducing the same to an annular distillation zone surrounding a substantial portion of the fractionating zone and vaporizing therefrom the gasoline and intermediate fractions thereof heavier than gasoline, fractionating the vapors thus evolved from the crude oil to condense the intermediate fractions heavier than gasoline, introducing such condensed 'fractions into direct contact with the cracked vapors undergoing dephlegmation to serve as a dephlegmating medium therefor, supplying the resultant mixture of reux condensate and intermediate fractions to the cracking zone for subjection to cracking conditions therein, and finally condensing the vapors uncondensed by said dephlegmation and fractionation.

4. A process which comprises subjecting hydrocarbon oil to cracking conditions of temperature and pressure in a cracking zone, removing cracked vapors from said zone and dephlegmating the same in a fractionating zone to condense insufficiently cracked fractions thereof, heating crude oil containingnatural gasoline in indirect heat exchange relationwith the cracked vapors undergoing 'dephlegmation by introducing 'the same to an annular distillation zone surrounding a substantial portion ofA the fractionating zone and vaporizing therefrom the gasoline and intermediateV fractions thereof heavier than gasoline, fractionating the vapors thus evolved from the crude oil to condense the intermediate fractions heavier thanV gasoline, introducing such condensed fractions into direct contact with the cracked vapors undergoing dephlegmation to serve as a dephlegmating medium therefor, supplying the resultantmixture i' reflux condensate and, intermediate fractions and the unvaporized portion of the crude oil to the cracking zone for subjectionto cracking conditions therein, and finally condensing the vapors uncondensed by said dephlegmation and fractionation. v

5. A process which comprises subjecting hydrocarbon oil to cracking conditions of temperature and pressure in a cracking zone, removing cracked vapors from said zone and dephlegmating the same in a fractionating zone to condense insuiciently cracked fractions thereof, heating crude oil containing natural gasoline in indirect heat exchange relation with the cracked vapors undergoing dephlegmation by introducing the,

same to an annular distillation zone surrounding a susbtantial portion of the fractionating zone and vaporizing therefrom the gasoline and inter-v mediate fractions thereof heavier than gasoline, fractionating the vapors thus evolved from the crude oil to condense the intermediate fractions heavier than gasoline, introducing such condensed fractions and unvaporized portions of the crude oil into direct contact'with the cracked vapors undergoing dephlegmation to serve as a dephlegmating medium therefor, supplying the resultant mixture of reflux conde te, unvaporized crude oil and intermediate fractions to the cracking zone for subjection to cracking conditions therein, and finally condensing the vapors uncondensed by said dephlegmation and fractionation.

JOSEPH G. ALTHER. 

